title: Clinical association between serum γ-glutamyltransferase levels and the development of insulin resistance in Korean men: a 5-year follow-up study.
abstract: OBJECTIVE
  In recent years, γ-glutamyltransferase has emerged as a predictor of cardiovascular disease, Type 2 diabetes mellitus, the metabolic syndrome and hypertension. However, it is not yet certain whether γ-glutamyltransferase is a predictor for insulin resistance. The aim of this study was to examine the longitudinal association between baseline γ-glutamyltransferase level and the development of insulin resistance in Korean men.
  
  
  METHODS
  We performed a prospective cohort study, involving 22 931 healthy Korean men without baseline insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR < 2.7) for 5 years. We checked the HOMA-IR serially to monitor the development of insulin resistance (incidence of HOMA-IR ≥ 2.7). A Cox proportional hazards model was used to determine hazard ratios for insulin resistance by quartile groups of baseline serum γ-glutamyltransferase levels.
  
  
  RESULTS
  During 81 208.6 person-years of follow-up, 3856 (16.8%) cases of insulin resistance developed between 2006 and 2010. After adjusting for multiple covariates, including baseline HOMA-IR, the hazard ratios (95% CI) for incident insulin resistance comparing the second to the fourth quartile of baseline serum γ-glutamyltransferase levels with the first quartile were 1.19 (1.06-1.33), 1.38 (1.23-1.53) and 1.58 (1.41-1.77), respectively (P for trend < 0.001).
  
  
  CONCLUSIONS
  Our findings show that serum γ-glutamyltransferase level could be a predictor of the development of insulin resistance in Korean men.
authors.affiliation: Department of Preventive Medicine, School of Medicine, Kyung Hee University.
authors.forename: J H
authors.initials: JH
authors.lastname: Ryoo
authors.forename: C M
authors.initials: CM
authors.lastname: Oh
authors.forename: H S
authors.initials: HS
authors.lastname: Kim
authors.forename: S K
authors.initials: SK
authors.lastname: Park
authors.forename: J M
authors.initials: JM
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D056910:Republic of Korea; D055815:Young Adult; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D015415:Biomarkers; D005723:gamma-Glutamyltransferase; C554782:gamma-glutamyltransferase, human